FIGURE3 Factors that can affect þooding
Event rainfall
Catchment vegetation
Catchment area
Slope
Dam releases
Soil types
Floodplain structures
Historic rainfall
Waterway size
Urbanisation
Land use
Tidal/storm surges
Run-off
Soil moisture conditions
Source: www.chiefscientist.qld.gov.au/publications/understanding-floods/what-is-a-flood.
Step2 Examine the diagram and the notes. Look at each part of the diagram. You will notice that various factors are identiýed, including rainfall, run-off, vegetation, size of waterways, soil type, slope and land use. Step3 Now consider the diagram as a whole. Studying the diagram helps you conclude that many factors affect þooding. It is more complicated than simply how much rain falls and how quickly. 8.12.3 Letmedo it Complete the following activities to practise this skill. 8.12 SkillBuilder activity Rainfall is the main cause of þooding in Australia. Floods can happen quickly (þash þooding) or slowly and are difýcult to predict. Cities and farms are often built on þoodplains (land that is subject to occasional þooding) because they provide access to water and good quality soil. In coastal areas, tides can add to þooding. 1. Apply your skills to interpret FIGURE4 and answer the following questions. a. How might a dam affect þood events? b. What is run-off? c. What effect can high tides have during þooding in coastal areas? d. Why are cities sometimes built on þoodplains? e. What are some effects of þoods?
Jacaranda Humanities Alive 7 Victorian Curriculum Third Edition
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